It seems like RPGs can't agree on what is a lot of damage. In the Dragon Quest series, an attack doing over 100 damage is a lot, but in Final Fantasy you're regularly doing multiple thousands of damage in an attack, whereas in dungeons and dragons an attack doing 30 damage would be a grievous wound, if not outright deadly.
@Rosemary There's a degree of sense here - Dragon Quest started on consoles where they were forced to represent HP as a maximum of 255, and so 100 damage is a significant chunk out of anything.
Final Fantasy started with this limitation, but went to larger numbers as soon as they could.
With D&D, a d20 is the primary resolution mechanic, so basing HP around something to do with that can be quite useful - same with games that use 2d6 having 7 harm as meaning dead